1. Field of the Invention
The present invention relates to a replaceable chuck for a percussion hand-held power tool such as, e.g., a combination hammer or a chisel hammer.
2. Description of the Prior Art
Replaceable chucks are usually releasably and replaceably secured in a hand-held power tool with a hand, without any auxiliary tool, using a manually radially displaceable, within certain limits, release sleeve that includes inwardly located locking means for formlockingly securing the chuck on a power tool spindle, with locking elements such as balls, extending through respective openings formed in the base body of the chuck and engageable in associated recesses of the power spindle. An anvil of a percussion mechanism of the power tool, which is axially displaceable, within certain limits, in the interior of the power tool spindle, applies direct blows to the impact tool receivable in the chuck. For securing the impact tool in the chuck, the chuck is provided usually, in addition to the release sleeve for securing the chuck and which is arranged on tool-side of the chuck, with another manually displaceable release sleeve, which is arranged on the impact tool-side of the chuck, for securing the working tool in the chuck.
U.S. Pat. No. 4,824,298 discloses a chuck a power tool-side release sleeve of which forms a manually tangentially displaceable, twist-on locking means for securing the ball-shaped locking element and having an inwardly located annular locking means that forms a circumferential, radially variable, locking guide.
German Publication DE 10 2004 042 465 discloses a replaceable chuck having a working tool-side release sleeve and a power tool-side release sleeve axially manually displaceable, against a spring-biasing force. The power tool-side release sleeve includes inwardly located locking means for formlockingly securing the chuck on a power tool spindle with balls extending through respective openings formed in the base body of the chuck and engageable in associated recesses on the power tool spindle. In high-power hand-held tools, in case of an idle stroke impact, the locking of the balls in the spindle recesses is not very reliable because of inertia forces that are generated by an impact load and cause strong axial vibrations of the release sleeve. The strengthening of the spring that preloads the power tool-side release sleeve, is limited by the user acceptance.
Accordingly, an object of the present invention is a replaceable chuck release sleeve of which is reliably secured on the drivable power tool spindle even at high impact loads.